When an offense performs poorly, it’s easy to label the quarterback, the receivers or coaches as scapegoats. However, the offensive line’s performance is also key to a team’s success.

The impact of solid pass blocking on offensive performance cannot be overstated. According to the game charters at Pro Football Focus, pressure is reducing the overall league passer rating from 96.5 to 66.2 this season. Teams are scoring 1.97 points per drive in 2017 when the quarterback has a clean pocket, yet just 0.98 points per drive when the offensive line gives up at least one sack, showing the effects poor pass protection can have for any quarterback on any team.

Analyzing which offensive line allows the most and least number of sacks is easy, but looking at the sacks themselves is paramount.

Overall, each sack saves a team 1.78 points this season, but it is important to note that not all sacks are created equal. A sack on fourth and 5, for example, is inherently more valuable than a sack on first and 10. According to the expected number of points scored given a combination of down, distance and yard line, a sack in the first instance saves a team almost three points (2.5) on average; a sack in the second scenario saves less than two points (1.7).

The San Francisco 49ers have the dubious honor of fielding the worst offensive line. That unit has allowed 27 sacks, second-most in the NFL, with the overall damage adding up to a loss of 56 points, averaging out to a touchdown per game. Consider the winless 49ers have lost five games by three or fewer points and it is easy to imagine what might have been for rookie Coach Kyle Shanahan in his debut if only his quarterback had better pass protection.

Week Opponent PF PA PD Points lost due to sack(s)
1 vs. Panthers 3 23 -20 10.7
2 @ Seahawks 9 12 -3 2.7
3 vs. Rams 39 41 -2 7.8
4 @ Cardinals 15 18 -3 6.0
5 @ Colts 23 26 -3 2.3
6 @ Redskins 24 26 -2 5.7
7 vs. Cowboys 10 40 -30 14.9
8 @ Eagles 10 33 -23 5.7

San Francisco isn’t alone. The 2-6 Indianapolis Colts, 3-4 Detroit Lions and 3-5 Chicago Bears are all at the top in terms of expected points lost due to their offensive line play, and, perhaps not coincidentally, at the bottom of the standings, too.

The best offensive lines reside in Dallas and New Orleans, who have surrendered nine and seven sacks, respectively. Not only do the quarterbacks on the Cowboys and Saints benefit from good pocket protection, but when they are sacked it isn’t as damaging as it could be. For example, the Cowboys’ offensive line has only lost a league-low 8.4 expected points via sacks in 2017, with the Saints close behind at 8.7. The Minnesota Vikings are third (16 expected points lost), losing almost double as many points despite yielding just one more sack than Dallas.

Team Sacks allowed in 2017 Expected points lost due to sacks
New Orleans Saints 7 -8.7
Dallas Cowboys 9 -8.4
Los Angeles Rams 10 -20.2
Minnesota Vikings 10 -16.0
Pittsburgh Steelers 10 -19.2

And no passer, or team, benefits more from a good offensive line than Drew Brees. According to Pro Football Focus, the Saints QB’s passer rating drops from 115.8 to 46.1 under pressure, almost as bad as the passer rating you get when you thrown an incomplete pass (39.6). Brees’ passer rating is 79.2 after a sack compared to 101.7 overall, illustrating the effect on him tends to linger for at least one more play.

The Saints’ offensive line also could look a lot better by the end of the season. New Orleans’ next two games are against the Tampa Bay Buccaneers and Buffalo Bills, who rank Nos. 32 and 28, respectively, for sack rate after adjusting for down, distance and opponent. And the Saints’ final four games are against the Atlanta Falcons (twice), the New York Jets and the Buccaneers again. The Falcons and Jets rank 26th and 30th for adjusted sack rate, which should be enough to keep Brees at his very best during the regular season.

Read more NFL: